1.

Arecibo Observatory, Puerto Rico

Diameter: 1,001 feet (305 meters)

The largest curved focusing dish on Earth by far is to be found in the Arecibo Observatory near the city of the same name in Puerto Rico. Operated by SRI International — a research institute born out of Stanford University — and with supervision from the National Science Foundation, the Observatory engages in radio astronomy, radar observations of the solar system and the study of the atmospheres of other planets. The enormous dish was built in 1963 inside the depression caused by a naturally occurring sinkhole. This somehow seems apt, as data about naturally occurring phenomena — albeit millions of miles away — interacts with man-made technology in the most wondrous of ways at Arecibo.

2.

Green Bank Telescope, USA

Diameter: 328 feet (100 meters)

The Robert C. Byrd Green Bank Telescope is located in the state of West Virginia, nestled in the middle of the United States National Radio Quiet Zone — an area of limited or banned radio transmissions, which greatly helps the telescope in operating to its highest potential. The telescope, which was completed in 2002, took eleven years to construct. Equipped with its massive 328-foot (100 m) dish, this fully steerable telescope has made several notable discoveries, including the discovery of the hydrogen gas-based Ophiuchus “superbubble,” which is located 23,000 light years distant.1.

3.

Effelsberg 100-m Radio Telescope, Germany

Diameter: 250 feet (76 meters)

The Effelsberg Radio Telescope is situated just outside of Effelsburg, a village in the southeastern potion of Bad Münstereifel, a town in western Germany. Built between 1968 and 1971, the telescope is operated by the Max Planck Institute for Radio Astronomy in Bonn. Equipped to observe pulsars, star formations and the nuclei of distant galaxies, Effelsberg is one of the most important instruments in the world’s network of super-powerful telescopes. Since it began its work in the early 1970s, ongoing improvements have been made — including low-noise electronics and a new surface for the dish — which have helped keep it among the elite of astronomical research institutions.